"The Shadow Duelist, Part 1", known as "Demon Deck of Darkness" in the Japanese version, is the fifth episode of the Yu-Gi-Oh GX anime. It first aired in Japan on November 3, 2004 and in the United States on October 17, 2005.
As the episode begins, Alexis Rhodes stands in front of an old building at night where she places a rose near the front of a statue and says, "Be at peace, wherever you are."
Jaden Yuki, Syrus Truesdale and Chumley Huffington are in their dorm, telling ghost stories using their cards. They would draw a card and, the higher the Level, the scarier the story must be. After drawing the Level 4 "Earthbound Spirit", Syrus tells a story about a swamp monster that lured a boy into its grasps with a "Dark Magician" card. Jaden draws the Level 1 "Sinister Serpent", and instead of an scary story, he tells them about a memory he had. When he was a kid, he used to hear strange voices coming from his closet. However, nothing was ever there, but his cards. Jaden however tells them that the strange thing was, he had been recently hearing the voices again, referring to Winged Kuriboh. Professor Banner comes to join in and ends up drawing the Level 12 "Five-Headed Dragon". For his ghost story, he tells them about an Abandoned Dorm on the edge of the island that had been shut down when many students went disappearing there. Banner tells them that the kids who disappeared were involved in Shadow Games, duels played using the Millennium Items. Syrus mentions that he had heard of the dorm before, so Jaden decides they should go the following night and check it out. Dr. Crowler overhears them outside and decides to use it to his advantage in getting rid of Jaden.
Meanwhile, in the city, a mysterious Duelist had beaten another Duelist in a Duel and claims to have taken his soul using a pendant resembling the Millennium Puzzle. After the other Duelist collapses, he receives a call on his cell phone, someone asking him to come to Duel Academy and he agrees to do so. The following day, Crowler watches Jaden fall asleep in class again and thinks to himself about how this class would be his last. That night, Crowler meets up with the mysterious Duelist by the lighthouse. He reveals himself as Titan, the Shadow Duelist. Crowler hires him to scare Jaden, so that the latter will exit Duel Academy and cease irking Crowler. In the English version, Titan states he'll send Jaden to the Shadow Realm, while in the Japanese version, he informs Crowler that he charges three months pay, regardless of the job.
Meanwhile, Jaden, Syrus and Chumley walk to the abandoned dorm and come across the rose Alexis has left behind. Syrus and Chumley are frightened by a snapping twig, which turns out to be Alexis. After asking why she was there, Alexis tells them she should be asking the same thing. After Jaden questions why Alexis was here, she snaps at him and tells them they'll be expelled if they're caught. Alexis reveals that the rumors about the disappearing students were true because one of those students that had disappeared was her brother. Jaden however still wants to see the dorm, so the three head inside. After they leave, Alexis is confronted and kidnapped by Titan. As the three search the dorm, they find most of the walls were covered in ancient Egyptian hieroglyphics of the Millenium Items as well as a picture of a student Jaden did not recognise. Meanwhile, Alexis wakes up and finds herself tied up in a coffin. Titan tells her that she was being used as bait for his trap. As she screams, the boys hear her and run through the dorm to find her. They later come across her "Etoile Cyber" card on the ground and find her located in a cave connected to the dorm.
Titan reveals himself to the three, and tells Jaden that the only way to free her was to beat him in a Shadow Duel. Jaden argues that Shadow Games don't exist, but Titan tells him that is what the others he had defeated believed as well. Jaden believes Titan must be behind the disappearances of the students and is willing to duel him to get Alexis back. Titan warns him, however, that in a Shadow Duel, the loser loses his soul.
Into the duel, Titan uses the pendant around his neck to create a black fog that slowly surrounds the room. Jaden suddenly begins to notices that parts of his body are mysteriously disappearing each time he loses lifepoints and Syrus and Chumley too begin feeling weak. Titan tells them that this was all due to the power of his Millennium Item.
Turn 3: Titan
Titan draws. He then Normal Summons "Terrorking Archfiend" (2000 → 3000/1500) in Attack Position since he controls an "Archfiend" monster. "Terrorking Archfiend" then attacks "Avian", but Jaden activates his face-down "Mirror Gate" to switch control of both battling monsters before damage is calculated. However, Titan activates the effect of "Terrorking Archfiend" to roll a die. If the result is a two or five, Jaden's "Mirror Gate" will be negated and destroyed. Titan gets a two, so "Mirror Gate" is negated and destroyed. "Terrorking Archfiend" then destroys "Avian" (Jaden: 4000 → 2000 LP). Jaden then activates his face-down "Hero Signal" to Special Summon "Elemental HERO Clayman" (800/2000) in Defense Position.
Turn 4: Jaden
Jaden draws "Pot of Greed" and subsequently activates it to draw two cards. He then activates "Polymerization" to fuse "Clayman" and "Elemental HERO Sparkman" to Fusion Summon "Elemental HERO Thunder Giant" (2400/1500) in Attack Position. Since "Thunder Giant" was Fusion Summoned, Jaden activates its effect to destroy "Terrorking Archfiend", but Titan activates the effect of "Terrorking Archfiend" to roll a die. Titan gets a five, so the effect of "Thunder Giant" is negated and "Thunder Giant" is destroyed.
According to Syrus (in the dub), Chumley failed math, which he states following the activation of Terrorking Archfiend's special ability when Chumley states that the odds are way in Jaden's favor, Chumley denies failing math, stating that he got a 54. Regardless of whether or not he passed math, his calculations in this situation were correct, as Titan has to get a 2 or 5, otherwise Jaden wins should the result being anything else; thus meaning that Jaden has 4/6 chance while Titan has a 2/6 chance.
In the Japanese version, Jaden is shown to have a second "Mirror Force" in his hand. However in the next episode, the second "Mirror Force" is not in his hand anymore and it's replaced with "Mirage of Nightmare".
The following cards appeared in this episode. Cards in italics debuted here.